Analyzing the circuits of neurons responsible for coding wavelength information requires knowledge of the populations of functional classes of cells, their neurotransmitters and connections. The goldfish retina serves as a model for visual and CNS processing. We intend to investigate the distributions and chromatic inputs of populations of retinal neurons using microchemical methods. Isolated retinas are incubated for short times (minutes) in media containing tritiated neurotransmitter substances, RNA precursors or sugars during physiological stimulation with various spatiotemporal patterns, colors and intensities of lights as well as in various states of adaptation. Uptake patterns will be studied autoradiographically in serial vertical and horizontal sections by light and electron microscope autoradiography. Analysis will center on resolving populations of bipolar, amacrine and ganglion cells that perform particular functions with respect to (1) chromatic inputs, (2) morphology, (3) synaptic connections and neurotransmitter content.